Major Mixtur GermanMajor Mixture EnglishMixtur Major GermanMixtura Major (unknown)

Major Mixtur is mentioned only by Irwin, who says
in his entry for Mixture:

A skillful device to increase intensity without hardness,
dissonance, or windiness is to use duplicate (in-tune)
ranks at the same pitch, such as two, perhaps even four,
2' Principals in a powerful Hauptwerk Major Mixtur.

Major Mixture is mentioned only by Irwin in a list
of mixture stops under the
heading “Diapason Chorus”, with no definition.
Mixtur Major and Mixtura Major are not mentioned in the literature.
We assume these names to be synonymous.

Examples

Osiris contains 16 examples of Mixtur Major,
ranging from IV to VIII ranks, all from the 2nd half of the 20th century,
and 8 examples of Mixtura Major, all from the 20th century.
No examples of Major Mixtur or Major Mixture are known.
Contributions welcome.